Report active resources when callback teardown is unbalanced

tests/test_etcp_stcp.c

@@ -339,6 +339,10 @@ static void callback_close_case(int reality, int side, unsigned action, unsigned
     etcp_conn_ref_free(test.retained);
     for (int i = 0; i < 2; i++) if (endpoints[i].inst) stop_endpoint(i);
     uasync_drain_immediate(ua);
+    if (ua->timer_alloc_count != ua->timer_free_count || ua->socket_alloc_count != ua->socket_free_count) {
+        debug_set_category_level(DEBUG_CATEGORY_SYS, DEBUG_LEVEL_INFO);
+        uasync_print_resources(ua, "callback close imbalance");
+    }
     CHECK(ua->timer_alloc_count == ua->timer_free_count && ua->socket_alloc_count == ua->socket_free_count);
     uasync_destroy(ua, 0);
     CHECK(u_get_allocated_count() == allocated);